The Quest for Speed at Sea - International Hydrofoil Society

The Quest for Speed at SeaDennis J. Clark, William M. Ellsworth, and John R. MeyerThis paper highlights the past, present, and future of the quest for speed at sea. It outlines thedevelopment of technologies and concepts to increase the speed of naval vehicles. Although commercial applicationsof high-speed marine craft flourish, the focus here is on high speed in naval missions.A historical context details significant attempts to increase ship speed, highlighting Carderock Division’smany contributions. The primary focus is after World War II, when the U.S. Navy began to seriously considerthe value of proposed concepts for planing craft, multihulls, hydrofoils, hovercraft, and hybrids.A discussion of current high-speed ship technologies follows, with an overview of limits and advantages,plus a review of operational experience. Costs of development, acquisition, and operations are weighed, followedby a summary of high-speed naval vehicles’ potential.IntroductionFor more than two hundred years, numerous effortsstrove to increase the speed of waterborne craft for bothmilitary and commercial applications. Increased speed ofnaval vehicles was called for in the vision of the Navy’sfuture set forth by the Chief of Naval Operations (CNO),Admiral Vern Clark, in “Sea Power 21.” In a recent conferenceon “Sea Power 21,” the CNO addressed the quality of“persistence.” In that particular context, he was referring to“persistence of combat capability,” but hecould have used the term just as appropriatelyto refer to the “persistence of technologicaleffort” described in this paper.Persistence in the quest for speed hasinvolved hundreds if not thousands ofscientists and engineers over manydecades dedicated to developing new shipand vehicle technology to give the Navycredible high-speed options.In the following sections, we highlightvarious approaches to the quest forspeed at sea and identify individuals whomade advances toward this goal possible.We need to understand the past to baselineour knowledge. A discussion of technologicallimitations and advancements,Figure 1. Sustention Triangle.operational experience, and cost effectiveness of speed follows.Numerous concepts employed in this quest appear in atimeline at the bottom of each page, divided in 20-year periods.They include planing craft, multihulls, hydrofoil shipsand craft, hovercraft, and hybrids. Most of the efforts toincrease speed involve getting the hull out of the water.Figure 1, the so-called Sustension Triangle, shows the liftforces raising the hulls above, or partially above, the watersurface.CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 3

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERHow High-Speed Ships and Craft AdvancedHere we discuss significant craft and concepts thatadvanced the quest for speed at sea over decades up to thepresent. We also identify key individuals who contributed tothese advances.Planing Craft DevelopmentThe planing hullform is perhaps the oldest, simplest,and most extensively employed member of the family ofmodern marine vehicles. As noted by Dr. Daniel Savitsky, 1modern planing hulls are designed to avoid the so-called“hump” problems, demonstrate good behavior in a seaway,have substantial useful load fractions, and have a potentialfor growth to displacements up to 1,000 tons or more. Theseattributes establish planing hulls as effective members ofnaval units. In the period 1970 to 1983, 327 fast attack unitsand 1,471 patrol craft were constructed and exportedworldwide. Their excellent cost-effectiveness ratio, simplicityof operation, miniaturized electronics, and relativelyheavy firepower attract the attention of many navies, particularlythose operating in restricted waters. The modernplaning hull now has better seakeeping characteristics withlittle sacrifice in calm water performance.In the mid-1970s, the U.S. Navy undertook anadvanced planing hull research program aimed at improvingseakeeping while retaining as much speed as possibleand improving the lift-to-drag ratio of the hull through themid-speed range. This research led to the development ofthe high length-to-beam ratio, high beam loading, doublechine, and moderate dead rise hull that met all of therequirements of good seakeeping and good lifting efficiency.This prototype hull, in a development led by Jerry Goreat Carderock, was designated the Costal Patrol InterdictionCraft (CPIC-X). It became the U.S. benchmark design thatmet the conflicting demands for the best compromise ofhigh speed and sea kindliness in one hullform with minimumcost and complexity.Unfortunately, the aggressive and successful planinghull research program initiated in the early 1970s subsidedin the late 1970s, when the U.S. Navy decided to emphasizeacquisition of large combatants capable of transiting theworld’s oceans. With this philosophy, problems can arisewhen we need to engage in limited warfare in areas wherethe larger ships cannot operate close to shore, or in the innerharbors or rivers.Since 1990, Donald L. Blount and Associates, Inc.(DLBA) has specialized in the design, testing, and constructionof motor yachts, commercial ferries, and military vessels.Blount began his career in the Carderock Planing CraftBranch. In 1992, the motor yacht Destriero, designed byDBLA, captured the international speed record during anunrefueled passage from New York to England. This 67-mvessel, which averaged a speed of 53.1 knots in the crossing,is powered by two LM-1500 gas turbines, and is capable of aspeed of 65 knots.With the current new interest in the U.S. Navy’s LittoralCombat Ship (LCS) program, the advanced state of planingship technology represented by Destriero is of interest as acandidate design for LCS. Don Blount is currently a memberof the Lockheed Martin LCS Team that selected the SeaBlade ship concept that builds on the hydrodynamic lineageof the Destriero.Multihull ShipsThe principal advantages of most multihulls are theirgreater deck area for a given length, excellent transverse stability,and potential for reduced wave-making resistance inthe high-speed range for displacement ships. These attributesmake the catamaran well suited to carrying low-densitycargo, for example as ferries. However, catamaran hullsare prone to pitching, and the cross structure can be subjectto large wave impact forces in rough seas.The concept of a multihull buoyantly supported vesselwas demonstrated at least a thousand years ago byPolynesian seafarers. The first known catamaran in theWestern world was a sailboat built in England in 1660.Beginning in the early 1800s, a sizeable number of steampaddle wheel-powered catamaran ferryboats and river craftwere built there and in the U.S. 2Efforts to solve the seakeeping and ride comfort problemsled, in the 1960s, to the small-waterplane-area twinhull(SWATH) ship configuration. Although the SWATHship is an important development with a number of desirablefeatures, it is not currently considered a high-speedconcept and is not covered in this paper.CatamaransDuring the past decade, the catamaran concept hasbeen employed mainly for commercial passenger transport.Since 1980, over 200 small high-speed catamaran ferrieswere built, mainly in Australia, Norway, and Sweden.The seakeeping of the catamaran is mixed. The hightransverse stability gives rise to pitch and roll at natural frequenciesthat are near each other. These frequencies, in turn,yield motions that feel more coupled than do those of themonohull. This effect has been described as a corkscrew4 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEAmotion, involving combined roll, pitch, and yaw. In thedesign process, knowledge of wave statistics for the actualoperating area is vital. Model seakeeping testing in a facilitythat can generate a reliable representation of wave environmentis also important for developing a successful design.Because of their effect on the resulting accelerations onboard a vehicle in a given seaway, the vessel’s natural periodsof pitch, heave, and roll are vital design parameters to consider.If any of the vessel’s natural periods are close to thewave encounter periods expected, the synchronism can leadto amplified motion responses.A design feature that demands thorough evaluation isthe shape and position above the still water level of theincreasingly commonly used cross-structure center hull. Inaddition to affecting vertical motions and accelerations, thisgeometric feature, if designed carefully, can improve resistanceperformance in waves.Semi-SWATHA semi-Small-Waterplane-Area Twin Hull (SWATH)ship is a combination of a SWATH ship in the forward halfand a conventional catamaran in the stern half. The combinationresults in vehicles with nearly equal seakeeping to aregular SWATH ship, but with superior speed/poweringperformance. The semi-SWATH ship concept also allowsthe integration of waterjet propulsion, by far the preferredchoice for high-speed ferries. The catamaran-like aft sectionsare more suitable for machinery arrangement andespecially for integrating waterjet propulsion. Like SWATHships, semi-SWATH ships offer a great deal of arrangeabledeck space and exhibit low resistance up to fairly highspeeds (40+ knots). 3The first and largest semi-SWATH ship in operation isthe Stena HSS 1500 with a displacement of about 4,000tons. Other Semi-SWATH passenger vessels are Stena HSS900, and Seajet 250. Although not quite as sensitive asSWATH ships, semi-SWATH ships are still somewhat sensitiveto overloading and trim. The small waterplane of theforward section makes them more susceptible, in particular,to changes in forward trim.In 1966, Carderock Division began a multi-year programof catamaran hydrodynamic and structural technologydevelopment to support the design of the ASR 21-class ofsubmarine rescue ships. By 1969, this development led tofurther in-house investigations of larger catamarans as aircapableships or small aircraft carriers.Wave-Piercing CatamaransThe increasing need for high-speed marine transport,coupled with the fact that passengers often experience discomfortin open ocean or exposed routes on conventionalcatamarans, created a need that the wave-piercer was developedto fill. Again, this hullform has twin hulls, but they arelong and slender with minimal freeboard and little buoyancyin the bow section. This configuration allows the bows tocut or pierce the waves, reducing the tendency of the vehicleto contour, thus providing lower pitch motions and accelerations,while carrying similar deadweight. 3The wave-piercing catamaran started in the early 1980s,with the development INCAT 28 m being the first to operateon a commercial route. Several companies have sincedeveloped their own approach to this type of design. One ofthe more famous wave-piercers is CONDOR II INCAT 78 m.CONDOR II reduces heave and pitch motions andaccelerations while in bow seas. Due to the twin hulls andthe separation between them, the vehicle has good inherentintact and damage stability. Large useable deck area resultsfrom separation of hulls that are still large enough aft toallow integration of waterjet propulsion and suitability formachinery arrangements.Due to the slenderness ratio of the hulls, these vehiclesare fairly efficient, and numerous operating vehicles providegood statistics regarding operational characteristics.Construction is more difficult than conventional catamaransdue to structural complexity of the forward hulls. Thewide beam of wave-piercer catamarans is also an issuewhere ports are not designed to harbor such vehicles. Wavepiercercatamarans may also experience lateral jerkymotions in beam seas.TrimaransA trimaran is a multihulled vehicle with three hullssupported by hydrostatic and hydrodynamic lift. There aretwo approaches to making a trimaran. The first approach isto have a very slender center hull supported by two outboardhulls that are smaller in both beam and length. Thesecond approach is to have longer outboard hulls and ashorter center hull forward. 3While trimarans have existed for centuries, only recentlyhas interest arisen in pursuing them as viable options forferry and military applications. The appearance in 1988 ofthe Ilan Voyager aroused interest in this concept. As of late,various defense departments investigated the use of a displacementtrimaran hull form for frigates and corvette-sizewarships, the latest of which is the Royal Navy Tritondemonstration trimaran. This ship has an overall length ofCARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 5

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYER105 m, a beam overall of 20 m, and a displacement of about1,200 metric tons.The attributes of trimaran hullforms include goodhydrodynamic efficiency, allowing higher speed with lowerinstalled power, adequate intact and damage stability characteristics,large usable deck area, good seakeeping qualities,and good directional stability. However, they are structurallycomplex due to cross structures connecting the outerhulls, and the lack of design experience entails some risk.Also, the maneuvering characteristics of these hullforms arerelatively poor, unless the outer hulls are large enough toaccommodate individual propulsion units.During the late 1980s, the U.S. Navy performed a seriesof model tests at Carderock to investigate a variant of theO’Neill Hullform that exploited the wave cancellationbetween the center body, the center surface-piercing strut,and the two outer hulls. Reference 4 discusses this hull formand points out that significant reductions in net total wavemakingresistance can be achieved at cruising speeds above24 knots. The resulting powering advantage of the WaveCancellation Multihull can be substantial. For example, fora 4,300-ton ship at a speed of 30 knots, the savings in effectivehorsepower (EHP) is between 22 and 28 percent comparedto the O’Neill Hullform and SWATH VII configurations.Reference 4 also shows data comparing several monohullsand the Wave Cancellation Multihull concept.Hydrofoil Ships and CraftOne of the earliest efforts to lift the hull from the waterwas by use of underwater wing-like lifting surfaces calledhydrofoils. These foils, like aircraft wings, follow theBernoulli principle. Air and water flowing over the curvedupper surface must move faster than that flowing beneath.This change in the flow pattern results in low pressure onthe top surface and high pressure on the bottom surface. Ata given speed, the forces generated lift the hull out of thewater.The Early YearsThe first hydrofoil craft was the product of an accidentin 1861. Thomas William Moy, an Englishman, studied theaerodynamics of wings by observing the vortices they created.He attached wings to his craft and tested it in the SurreyCanal. To his surprise it rose from the water and, unintentionally,he discovered hydrofoils.In 1909, CAPT Holden C. Richardson USN (Ret), thena young Naval Constructor and an early seaplane designer,sought a solution to landing aircraft on the sea. Inspired byEnrico Forlanini in Italy, who proposed using hydrofoils aslanding gear for seaplanes, he fitted a set of submerged foilsto a dinghy. While under tow in the Philadelphia river, itlifted from the water and “flew” at a speed of about 6 knots.Richardson’s efforts in hydrofoil design continued at leastuntil 1911.A hydrofoil craft designed and built by the Italian aircraftdesigner Enrico Forlanini was the first successful suchcraft manned and motor driven. In 1906, he made test runsof a 1.6-ton craft on Lake Maggiore in Italy. The craft had a60-HP engine driving two counterrotating air propellers,and reached a top speed of 42.5 mph.Alexandra Graham Bell and his co-worker and friend F.W. (Casey) Baldwin became interested in hydrofoils as earlyas 1901. During a world tour, Bell and Baldwin rodeForlanini’s boat on Lake Maggiore. On returning toCanada, Bell purchased a license to build and develop theForlanini ladder-foil system in North America. WithBaldwin as designer and engineer and Bell as advisor, theybuilt and tested a number of “hydrodomes.” Bell failed tointerest the U.S. Navy in the HD-3 and turned his attentionto sailboats. With the U.S. entry into the European war,Bell’s hopes for hydrofoils revived when the U.S. NavyDepartment called for proposals to design and build subchasers.However, Bell’s offer to build two HD-4 hydrofoilcraft for that purpose was rejected. The Navy sent him two50-HP Renault engines, and design work on an HD-4 continuedand incorporated all that had been learned from previoussuccesses and failures. With the Renault engines, thetop speed of the HD-4 was only 54 mph, but it performedwell with good stability and took waves without difficulty.With Bell’s report of the success of these trials, in early 1919the Navy sent him two 350-HP Liberty engines. Using theseengines, on 9 September 1919, HD-4 set a new world’smarine speed record of 70.86 mph that stood for the nextdecade. A year later, Bell got observers from the U.S. Navyand the British Admiralty to watch demonstrations of HD-4. Although all observers made enthusiastic reports, neithercountry saw fit to place an order. Some felt such a craft wastoo fragile for naval action at sea.From 1927 to 1936, Hanns Von Schertel, a youngGerman engineering graduate of the Technical University inBerlin-Charlottenburg, designed eight experimental hydrofoilcraft. After several disappointing experiences, hebecame convinced that the only way to ensure stability ofsubmerged hydrofoils was by use of an automatic lift controland a submerged depth sensor. In the late 1930s, heteamed with Sachsenberg Shipyards in Germany to bid onthe German Navy’s request for proposals for a hydrofoilcraft to be used as a military personnel carrier over shortdistances. The Schertel/Sachsenberg entry, designated theVS-6, was selected, and several VS-6 models of about 15tons were built.6 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERIn January 1960, a group of experts from the UnitedStates, United Kingdom, and Canada concluded that ahydrofoil ship promised significant improvement in ASWcapability. The hydrofoil concept was technically sound,and it complemented the hydrofoil development thenunderway in the U.S. Navy that involved fully-submergedactively-controlled foil systems. At this point, the CanadianNaval Board recommended proceeding with design andconstruction of a 200-ton ship, designated the FHE-400(Fast Hydrofoil Escort).Hull construction of the FHE-400, designed byDeHavilland Aircraft, was begun at Marine Industries Ltd.,Sorel in 1964, and was completed in 1965. The hull waserected upside down to permit maximum use of downhandwelding of aluminum, and large sections of the shellwere welded as sub-assemblies. Unfortunately, in the finalstages of outfitting, in November 1966, a major fire brokeout in the engine room during tests of the auxiliary gas turbine.The center of the ship essentially had to be rebuilt. Itwas not until July 1968 that the ship could be transferred toHalifax on the “slave dock” (a floating barge) that served asher maintenance base.From September 1968 to July 1971, the ship, christenedBras-D’Or, logged 552 hours hullborne and 96 hours foilbornein trials. Regrettably, significant rough-water datawere small in number. However, hullborne seakeeping wasexceptionally good. Foilborne, under full load, she exceededher calm water design speed, achieving 63 knots in 3- to 4-ft waves. She took off and landed smoothly, and exhibitedgood stability and control at all speeds.In July 1969, with the ship docked to repair persistentfoil-system leaks, a large crack was discovered in the lowersurface of the center main foil. When the neoprene coatingwas removed, an extensive network of cracks was found. Anew foil element was installed, but in July 1971 this foil alsodeveloped severe cracking. Clearly, the use of extremelyhigh yield-strength maraging steel was a major problem dueto stress-corrosion cracking.A decision was made in October 1971 to lay up theship. However, this decision was not due to the structuralproblem with the foils, but rather was due to a change indefense policy issued in August 1971. This change in policyassigned priority not to ASW, but to the protection of “sovereignty”and the surveillance of Canadian territory andcoastlines. This decision would place the ASW hydrofoilship behind at least three major procurement programs forthe Maritime Command. As a result, on 2 November 1971,the Minister of National Defence announced in the Houseof Commons: “A decision has been made by the departmentto lay up the hydrofoil Bras D’Or for a five-year period.”Unfortunately, circumstances never occurred to restore theship to active service and the FHE-400 eventually became amuseum display sitting on its slave dock.The U.S. Navy Begins Exploratory Research ProgramDuring the early 1950s, the U.S. Navy demonstratedvarious experimental craft. 6 A common remark was “This isa lot of fun, but what would the Navy ever do with hydrofoils?”This viewpoint seemed to permeate the entire earlyhistory of U.S. Navy hydrofoil development. The MarineCorps’ complaint that the speed of approaching the beachhad not changed since William the Conqueror headed for abeach in 1066 sparked the Navy’s interest in hydrofoil landingcraft. As a result, a program began in 1954 to evaluate ahydrofoil-supported landing craft designated the LCVP. Arequest for proposals (RFP) for an LCVP hydrofoil wasreleased by the Navy. An enthusiastic experimenter withhydrofoil craft, Christopher Hook, joined Bob Johnston,President of Miami Shipbuilding Corporation, to respondto the RFP. To the Navy’s surprise, they won the competition.The LCVP was called Halobates, named for a sea-goinginsect with forward-extending feelers. One of the requirementsof the design was that the craft be capable of flying inshallowing water. As it approached the beach for a landing,the foils were retractable with diminishing foil depth, witha continuous transition from foilborne to hullborne as thewater shoaled. During flight test, Halobates reached speedsup to 34 knots in five-foot waves. Its performance wasdemonstrated over a range of weights from 23,290 to 31,165pounds. The Navy disagreed with the use of the large feelerarms and considered them quite impractical. Fortunately, aMiami Shipbuilding electronic autopilot was ready to go. Astep resistance, on the leading edge of the forward struts,provided a height signal. The Navy also became interestedin the use of lightweight gas turbine engines. As a result,when an electronic autopilot was installed in Halobates, anAVCO T-53 gas turbine was also installed.From 1951 to 1954, funds were budgeted to build a3,500-ton hydrofoil cargo carrier with a destroyer-type hull.The Office of Naval Research (ONR) was given Navy programmanagement responsibility supported by the Bureauof Ships, Bureau of Aeronautics, and NSWC Carderock. Thebasic research was undertaken by the HydrofoilCorporation of America, a non-profit organization formedby Dr. Vannevar Bush, President of the Carnegie Institutionand scientific advisor to the President of the United States.LCDR Patrick Leehy was designated Project Officer inONR. CDR Robert Johnston later replaced him. In 1954, itwas concluded that the development of a propulsion systemfor a 3,500-ton hydrofoil might tax the total capability ofU.S. industry. On this note, the project was terminated.8 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEAA small 5-ton, modified Chris-Craft perhaps did themost to interest the U.S. Navy in the future potential ofhydrofoil craft. The craft had its genesis in the 1950s at thenaval architecture firm of Gibbs & Cox. They assembled ahydrofoil team headed by Tom Buerman that included Dr.John Breslin, Dr. S.F. Hoerner, L.E. Sutton, and RichardBrowne. In 1954, Sutton and Browne were assigned tosupervise construction of an autopilot-stabilized test craftthat was to become Sea Legs. It had a 28.5-ft hull with a 9.0-ft beam, full-load weight of 10,550 lbs. The foils were aluminumwith a German section and were arranged in acanard configuration. For the autopilot, Richard Brownestarted with the basic technology developed by the DraperLaboratory of MIT and assembled a practical workingautopilot with 160 vacuum tubes. For the height signal, itutilized a sonic height sensor. The autopilot and height sensorwere significant technical advances.Sea Legs’ first flight in 1957 was impressive. 7 Theautopilot stabilized the craft in rough seas and it achievedspeeds up to 27 knots. After Navy personnel witnessed thetrials in the New York area during late 1957 and early 1958,Sea Legs got underway to Washington, DC. During the transitin the open ocean, accompanied by the U.S. Navy’s PT-812, Sea Legs averaged 23 knots in 4 to 5-ft waves. Thehydrofoil craft demonstrated seakeeping and performanceabsolutely impossible for conventional boats of the same, oreven larger size. Those aboard reported a dry, comfortableride, while conditions on the PT-812 were quite differentindeed. Three Navy Commanders, William Nicholson,Randolph King, and Kenneth Wilson headed this adventure.When Sea Legs arrived in Washington, a number of interestedmilitary and government personnel were embarked forfurther demonstrations. They included the CNO, AdmiralArleigh Burke.In 1962 and 1963, Sea Legs underwent more detailedevaluation by the Carderock Division. It was extensivelyinstrumented and provided at-sea data for future designs.This small boat was the single most important forerunner ofthe U.S. Navy’s decision to get serious about the use ofhydrofoil ships and craft in the future Navy fleet. In recognitionof its importance, Sea Legs is presently on exhibit inthe Mariner Museum in Newport News, VA.The U.S. Navy Gets SeriousWith the growing momentum generated by theexpanding technology base, and the demonstrated attributesof hydrofoils for naval missions, the Bureau of ShipsPreliminary Design Branch began a design study, in late1957, of hydrofoils for ASW. This study was strongly influencedby Canada’s development of the hydrofoil ASW shipFHE-400. In a letter dated 24 January 1958, OPNAVrequested BuShips to study a hydrofoil for harbor defenseand coastal patrol. Designated the PC(H), when comparedto the sub chasers PC(S) and SC, it appeared capable of performingthe mission of these patrol craft in a superior manner.As a result, the PC(H) was substituted for the PC(S) andSC in the FY60 shipbuilding program. With the blessing ofOPNAV, PC(H) design work continued until March 1959when the preliminary design was completed. Based on theexperience with Sea Legs, the selected design was a fullysubmerged,autopilot-controlled foil system in a canardconfiguration. It was thus that the many years of hydrofoilresearch finally bore fruit with the design and acquisition ofwhat was expected to be the U.S. Navy’s first operationalhydrofoil ship.The contract plans and specifications for PCH wereturned over to BuShips Code-526, the Mine, Service, andPatrol Craft Branch, otherwise known as the Type Desk.The contract for detailed design and construction was to bebid on a competitive, fixed-price basis. In June 1960, TheBoeing Company in Seattle, WA was awarded a contract fora fixed price of $2.08 million to do detailed design and construction.Boeing’s research and entry into hydrofoil programsbegan in 1958 with in-house funding. A MarineGroup was formed in 1959 as part of the AerospaceDivision. Later it became Boeing Marine Systems. Hull loftingbegan in the Fall of 1960 at Martinac Shipyard inTacoma, WA. The ship, designated the PCH-1, was launchedin conventional fashion the evening of 17 August 1962, andchristened High Point, after High Point, NC.In retrospect, it seems no surprise that the builder’s trials,post-delivery tribulations, special performance trials,and final acceptance trials, clearly demonstrated that theship was not ready, and possibly might never be ready, fordelivery to the fleet. This fact was finally recognized, andOPNAV made the decision to transfer the ship to NSWCCarderock to continue development of the technology basefor design of naval hydrofoil craft and ships. The followingtwenty years of the PCH-1 trials, modifications, and explorationof mission applications appear in detail inReference 8.In 1961, BuShips initiated the Hydrofoil AcceleratedResearch Program (HARPY) directed toward bigger, better,and faster hydrofoil ships. James Schuler, HydrofoilProgram Manager, initially directed the program with assistancefrom Owen Oakley and Ralph Lacey in Code 420. Theneed for a high-speed test craft to investigate sub-cavitating,ventilated, and super-cavitating foil systems was evident. InJune 1961, BuShips awarded a contract to Boeing to designand construct a high-speed test craft that could be highlyinstrumented and propelled at speeds up to 100 knots. ThisCARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 9

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERcraft, named FRESH-1 (Foil Research Hydrofoil), waslaunched on 8 February 1963. Powered by an aircraft turbineengine on 3 May 1963, it attained a speed of 80 knots.FRESH-1 characteristics and test operations appear inReference 9. During one of its trial runs, in a turn, the craftbecame unstable due to foil ventilation and capsized.Fortunately, there were no casualties. As a result of theNavy’s decision to delay, CNO Admiral Zumwalt’s quest fora 100-knot Navy, FRESH-1 was laid up.On 10 November 1966, NSWC Carderock establishedthe Hydrofoil Special Trials Unit (HYSTU) as a tenantactivity of the Puget Sound Naval Shipyard (PSNS). It wasstaffed by LCDR Karl Duff, USN as the Officer in Charge,and a number of technical and administrative personnel.The Officer in Charge of HYSTU, and the assigned hydrofoilships were administratively assigned to CO&DCarderock with local control by COM 13 in Seattle. Civilianpersonnel were responsible to the Technical Manager of theHydrofoil Development Program Office at NSWCCarderock.During the period when PCH-1 was under construction,the Navy contracted with the Grumman Corporationfor the design of the 320-ton hydrofoil ship AGEH-1. 10Lockheed Shipbuilding in Seattle, WA constructed it. Theship, christened Plainview, after Plainview, TX and NY, wasdelivered to the Navy in 1969. At that time it was the largesthydrofoil ship in the world. It was originally planned as anASW ship and was designed to achieve speeds of 90 to 100knots. However, due to experiences with other hydrofoils,the decision was made to install only two LM-1500 gas turbineswith space available for adding two more, thus limitingthe speed to a nominal 50-60 knots. Also, rather thandeploying the ship to the fleet, it was assigned to theCarderock Hydrofoil Special Trials Unit for additional R&Dtrials.The first U.S. Navy operational hydrofoils delivered tothe fleet were the patrol gunboat hydrofoils (PGHs). TwoPGHs were built, one by Grumman, Flagstaff (PGH-1), andone by Boeing, Tucumcari (PGH-2). Although designed andbuilt to the same performance specifications, their configurationswere substantially different. PGH-1 was propellerdriven and had a conventional foil distribution. PGH-2 waswaterjet propelled and had a canard foil system. They weredelivered to the Navy in 1968 and both saw service inVietnam, making them the first U.S. Navy hydrofoils incombat. The operational experience gained with thesehydrofoils, particularly the Tucumcari, provided the confidencenecessary to proceed with the Patrol Hydrofoil Missile(PHM) ship program.NATO Navies Join Hydrofoil ProgramIn 1972, three NATO navies formally agreed to proceedwith the joint development of a high-speed hydrofoil combatant.A Memorandum of Understanding (MOU) wassigned by the United States, Federal Republic of Germany,and Italy. A letter contract was awarded to the BoeingCompany for a feasibility study, and the design and constructionof two Patrol Combatant Missile (Hydrofoil)Ships. 11 Although the initial contract called for two leadships, program cost growth in August 1974 forced suspensionof the work on the second ship. PHM-2 was later incorporatedinto the production program. Nearly six yearselapsed from the signing of the letter contract for the designand construction of the lead ship, PHM-1, in November1971. She was commissioned as USS Pegasus in July 1977. Itwas not until 1981 and 1982 that the five additional PHMsjoined the PHM-1 to form the desired squadron of six ships.The PHM Squadron was based in Key West, FL and assignedto support the U.S. Coast Guard in intercepting drug smugglerswho were using high speed “Cigarette” boats. 11 Theiroperational experience is described in a following section.To the dismay of the advocates of Naval hydrofoil ships, on30 July 1993 at the Naval Amphibious Base, Little Creek, VA,the Navy decommissioned the entire Class of PHMs in oneday, the first such act in naval history. The ships were inmint condition, had fulfilled all expectations for their performance,and had another 15 years of useful life. The CoastGuard indicated they would be glad to take over thesquadron, but the Navy had to provide the operating funds.The Navy refused. In time, except for one of the ships, allothers were sold for scrap. Since that time, the Navy has notoperated hydrofoil ships.U.S. Navy Hydrofoil Effort Focused On Design ConceptsSince the mid-1980s, advancement of hydrofoil conceptsin the U.S. Navy has been restricted essentially to“paper” studies, although subsystem technologies have continuedto advance. Even though currently there are nohydrofoil ships in the U.S. Naval fleet, interest continues indeveloping the technology and improving the subsystemsfor these ships. The hydrofoil community, of whichCarderock is a major contributor, continues to carry outconceptual studies and feasibility designs of relatively largehydrofoil ships to suit a variety of mission applications. Inthis respect, a fundamental limitation impacts the growthpotential of hydrofoil ships. It is the “square-cube” law thatstates the lift developed by foils is proportional to their planform area (the square of a linear dimension), whereas theweight to be supported is proportional to the volume (thecube of a linear dimension). Thus, as the size of the ship10 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERtotype LACV-30s. They were an adaptation of Bell AerospaceTextron’s commercial ACV Voyageur with major improvements.Two Pratt & Whitney ST6T-76 twin-pack gas turbineengines, rated at 1,800 SHP, powered them. They each drovethree-bladed, 9-foot diameter, Hamilton Standard variablepitchpropellers. Based on the experience with these two prototypes,the Army purchased a total of 26 LACV-30s.Although the LACV-30 fulfilled a major need in theArmy Logistics Over The Shore (LOTS) requirement, somerequirements remained unmet. The transportation ofheavy, outsize cargo quickly exceeded the LACV-30 capability.The Army approved a Letter of Agreement for a LAMP-H on 24 May 1982. The LAMP-H was required to transportheavy equipment, LOTS support equipment, the M-1 tank,tracked and wheeled vehicles, 20- and 40-ft containers, andgeneral cargo. In response to these requirements, the Armyevaluated four candidate concepts: the Marine Corps LCAC,a modified U.K. SR.N4 ferry, an air cushion barge, and amodified LACV-30.The Army operated the LACV-30s up until the mid1990s. Most of these were ultimately turned over to a NativeAlaskan corporation that continues to lease them to meetrequirements in Alaska.Navy and Marine Corps Begin LCAC ProgramThe Landing Craft Air Cushion (LCAC) is a dramaticinnovation in modern amphibious warfare technology. Itprovides the capability to launch an assault from over thehorizon, thereby decreasing the risk to ships and personneland creating uncertainty for the enemy as to where theassault might occur.In the 1965-1970 period, the U.S. Navy and MarineCorps undertook studies of the application of the air cushionprincipal to improve amphibious landing craft. Two craftwere designed and constructed: the JEFF (A) by AerojetGeneral Corporation, and the JEFF (B) by Bell Aerospace. InOctober 1977, Carderock established the Assault LandingCraft Experimental Trials Unit in Panama City, FL for thepurpose of testing these two air cushion prototypes. The Jeff(B) was launched on 17 December 1977 and made its firsttrial run reaching a speed of 42 knots. The Jeff (A) made itsfirst run at Panama City, FL on 17 October 1978.Based on the results of these trials, Bell AerospaceTextron was awarded a contract in 1981 to begin the productionof the Landing Craft Air Cushion (LCAC). Thesecraft are powered by four Avco-Lycoming TF40B gas turbines,each rated at 3,955 SHP (two for propulsion and twofor lift). The craft are capable of carrying a 60-ton payloadand 75 tons in overload. They can carry a main battle tank,with a range of 200 nautical miles at 40 knots with payloadin sea state 2, and 300 nautical miles at 35 knots withoutpayload. Four LCACs can be carried in the LSD 41 class and3 in the LSD 36 class.On 29 June 1987, the LCAC was approved for full production.Textron was awarded a contract to deliver 48 craftthrough FY 1989. Lockheed Shipbuilding was also selectedas a second source. As of 1995, 82 LCACs were delivered.The largest deployment of LCACs took place in January1981 with 4 detachments of 11 craft reported for duty in thePersian Gulf in support of Operation Desert Storm.As of this date, 92 LCACs have been delivered, andTextron Marine and Land Systems is currently under contractto perform a Service Life Extension Program (SLEP) toextend the craft’s life beyond 20 years.Why Surface Effects Ships (SES)?Although the Surface Effect Ship (SES) has a number ofunique advantages, the principal motivation behind theconcept is that the air cushion, which supports the majorityof the weight of the craft, significantly reduces the resistanceto forward motion at high speed. It also helps to mitigate theeffect on craft motions and accelerations when operating inrough seas. Although power is required to create and sustainthe air cushion, the reduction in resistance is so large at highspeed that the sum of lift and propulsion power is significantlyless than that for the equivalent monohull.SES Development BeginsIn 1959, Ted Tattersall in the U.K. initiated developmentof the first solid sidewall hovercraft, later called theSES. At about the same time in the U.S., a small team led byAllen Ford, at the Naval Air Warfare Research Departmentof the Naval Air Development Center (NADC), invented asimilar concept called the “Captured Air Bubble.” This hovercrafthad rigid sidewalls that penetrated the water surfaceand contained an air cushion between them sealed fore andaft with bow and stern seals. Ford claimed that, despite theloss of amphibious capability, the design resulted in a muchhigher lift-to-drag ratio due to the reduction of air leakage.The Tattersall team, with the backing of William Denny& Bros., licensees of Hovercraft Development Limited, builtthe first U.K. 70-foot manned model with a cushion Lengthto-Beam(L/B) ratio of 7:1. It had a weight of 5 tons and waspowered by two 35-HP Mercury outboard motors.Introduced on 22 June 1961 as the D.1, the craft made 18knots and lifted the cross-structure above the surface of thewater. It was successful enough to lead to the building of the70-passenger, 20-knot GRP SES D.2 that went into experimentalpassenger service in 1963.12 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEAIn the U.S., Allen Ford launched the XR-1 in May 1963.It was 50 feet long, weighed 10 tons, and was propelled by aJ-79 jet engine. The craft’s Length-to-Beam (L/B) was 3.5and, with a more powerful J-85 engine, it achieved a speedof 60 knots. In 1965, Ford joined Harvey Chaplin atCarderock. His original design went through eight majormodifications leading up to the XR1-E, some 22 years later.Four were built as commercial ferries capable of carrying 70passengers at a speed of 27 knots, subsequently modified togive a maximum speed of 34 knots.Although the top speed of early operational SESs wasless than 40 knots, the historical thrust was to develop an80- to 100-knot capability. In 1969, design and constructioncontracts were awarded to Aerojet General for the SES 100-A and to Bell Aerospace for the SES 100-B test craft. Both ofthese 100-ton craft were extensively operated, and validatedtheir architectural and engineering technologies and subsequentmodifications. The SES 100-B established a sustainedspeed record of 91.9 knots in a slight chop on LakePonchartrain, and also operated at 35 knots in 6- to 8-footwaves. In 1978, the SES 100-A served as a scale model for thedesign and construction of the Navy’s 3,000-ton, 80-knotprototype, called the 3K SES. Unfortunately, the 3K SESprogram was terminated in December 1979, just threeweeks before beginning hull construction and after anexpenditure of over $400 million. This termination, basedmainly on the lack of a mission for a large prototype, frustratedthe thrust for a 100-knot Navy.The SES-200: Exploring New GeometriesMilitary applications of SESs required examination ofthe early geometry. Low L/B ratios and thin side hulls characterizedmost of the early SESs. They were designed tooperate almost exclusively on cushion at high post-primaryhump drag speeds. This design proved to be efficient forferry operation but not for military applications.In the late 1970s, Bell Aerospace joined with HalterMarine to build the BH-110 SES as a shuttle to serve oil rigsin the Gulf of Mexico. Together they built four of these craft.Unfortunately, the 1970s moratorium on oil drilling in theGulf resulted in a loss of this market. They tried to find newcustomers about the time the 3K-SES program was terminated.The focus of Navy SES interest turned to lower technologyand somewhat lower speed. Bell Halter developedCoast Guard interest in a small, fast cutter to deal with drugsmuggling “Cigarette” boats in the Florida Keys. A cooperativetrials program was conducted by the Navy and theCoast Guard using a BH-110 for about a year. This programresulted in sufficient interest for the Navy to acquire oneBH-110, and for the Coast Guard to acquire the other three.In the early 1980s, in order to advance the technologybase of high L/B SES craft, the Navy awarded Bell a contractto stretch their BH-110 with a 50-foot extension of the hull.This craft was designated the SES-200, which was about200-tons displacement. Bell also installed a prototype ridecontrol system. The result of the stretch to a higher L/B ratiogave better seakeeping and a lower operating cost below theprimary hump. Special note is made of this craft because ofits extensive employment in advancing the SES technologybase.In late 1984, the NAVSEA SES Program Office was disestablished.The SES-200 and the Patuxent River TestFacility were transferred to Carderock in an attempt to keepthe SES technology program alive. Jack Offutt was put incharge of the craft’s operation, which continued fromJanuary 1985 until 1990. Joint trials were run with the CoastGuard and CINCLANTFLT deployments in fleet exercisesand as a test platform for live-fire exercises. The craft alsomade port calls in the Caribbean. It then was deployed tothe NATO Special Working Group and was involved withtrials for the U.K., France, Spain, Canada, and Norway in the1984–86 timeframe. After the NATO deployment, the craftwas re-engined with high-speed diesels and waterjet pumps,and trials at higher speeds were conducted.In circa 1990, management responsibility for SES-200was transferred to the Carderock Combatant CraftDepartment in Norfolk, VA. The attempt to find additionalcustomers was not successful, and the craft became a liabilitywithout funds for maintenance and operation.Discussions of alternatives were held with ONR, and it wasdecided that the craft could be used for a program at PacificMarine Navatek in Hawaii, under Steve Loui. They werelooking for a way to test lifting body technology on a largescale. SES-200 was given to Loui to modify for a test as aHydrofoil Small Waterplane Area Catamaran (HYSWAC).The hull was modified to a catamaran with a lifting body. Asof this writing, it has been undergoing a hull modificationin the shipyard, and tests are expected to begin in the summerof 2003.SES Design and Construction ExpandsIn the decade of the 1980s, there was a worldwideexpansion in the design, construction, and operation ofhundreds of SESs, primarily as commercial ferries withsome military applications. Most were relatively small (lessthan 200 tons) with operating speeds of 25 to 40 knots. TheEuropean experience definitely proved the economic feasibilityof SES ferries.In the early 1980s, a contract was awarded to TextronMarine Systems for a number of U.S. Navy GRP SES MineCARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 13

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERCountermeasure Craft (MSH). The contract was terminatedbefore construction of the first craft. At this same time,the Navy also developed the concept of a SES SpecialWarfare Craft Medium (SWCM). A contract was awarded toRohr Marine (RMI) but terminated before construction ofthe first craft. During this period, the technology lead transferredback to Europe, with the SES concept being aggressivelypursued for commercial and military applications.Notably, in 1987, the Swedish Defence MaterialAdministration (FMV) initiated a comprehensive SES R&Dprogram involving a number of Swedish firms and governmentagencies. This program led to a building contract withKarlskronavarvet AB for the stealth test craft Testrigg Smyge.This craft was aimed at evaluation of stealth optimization,new weapons systems, cored GRP construction, the SESconcept, and waterjet propulsion for future MCMs andcombatant craft. Construction was completed in 1991.The great proliferation of SES craft up to 1991 is extensivelycovered in the Lavis and Spaulding paper, Reference13. Significant developments in SES ships and craft duringthe last decade are provided by Robert A. Wilson, one of thepioneers on the Carderock SES technical team. He is coholderof six patents relative to SES, and from 1965 to 1980was Deputy Head of the SES Division in the Aviation andSES Department. He retired from the Carderock Division in1996. Since then, he has continued to follow worldwidedevelopments of surface effect ships and craft.Development of SESs is continuing in Scandinavia andJapan. The Swedes and the Norwegians brought along theconcepts that resulted in the HMS Smyge. It demonstratedthe ability of the shape to reduce signatures. Also, theNorwegian Cirrus passenger ferries proved popular in serviceon the fjords north of the Arctic Circle, and in otherareas.UMO Mandal is using SES technology as the basis forits design and construction of naval vehicles, particularlyMine Countermeasure Vessels (MCMVs) and Fast PatrolBoats (FPBs). The MCMVs are specially fitted for minehuntingand minesweeping. The rationale for selecting theSES concept is its lower acoustic and magnetic signatures,higher tolerance of underwater explosions, improved sonarconditions, higher strength-to-weight ratio, shallow draft,precise maneuvering, good seakeeping in heavy weather,high speed and low noise levels, and improved crew comfortcompared to other concepts. UMO Mandal is currentlybuilding four SES minehunters and five SES minesweepersfor the Royal Norwegian Navy.UMO Mandal’s Skjold-Class Fast Patrol Boats are similarin design to the MCMVs, but are smaller and faster. Likethe Smyge, the Sjkold-Class capitalizes on the adaptability ofthe SES’s hull and materials used to reduce the radar signature.They have delivered one prototype FPB to the RoyalNorwegian Navy and have an option for production of aseries of another seven units.SES development is underway in Japan since the 1970s,with two SES development teams. One team was from theJapan Defense Agency, whose goal was a missile boat; theother team was from the Japanese Ministry ofTransportation, whose development target was a cargo carrier.The Ministry of Transportation developed the TSL-Aunder the Techno Super Liner program. This test platformwas named Hisyo. After its initial trials, Hisyo was sold tothe Shizuoka Prefecture Office and, after some modifications,used as a ferry boat or in an emergency as a rescueboat. The Japanese Defense Agency built two test platformsnamed Meguro and Meguro-2.The positive experience with the TSL-A was its goodseaworthiness, giving the Japanese the confidence that alarge SES could be used commercially around Japan if itslength was over 100 meters. On the other hand, the negativeexperiences were the difficulty of manufacturing, the maintenanceof the large fore and aft seals, and the expensive costcompared to a monohull high-speed ferry with the samecapacity. Nevertheless, Mitsui is designing, and plans toconstruct, a large SES ferry for cars, trucks, and passengers.This ferry is nominally 140 meters long with a displacementgreater than 1,000 tons, and cruises at 30-35 knots. Its onewayoperating time is expected to be 14 hours includingmultiple stops. The projected launch date is in 2004.Is there a future for the SES in the U.S.? U.S. SES commercialderivatives such as the Air Ride Craft, Inc. ferry conceptexist. Also, the Navy’s current Littoral Combat Ship(LCS) competition states the need for a low-cost, fast, highendurance,small surface combatant. This competition hasproduced one SES concept. The National Defense Magazinenotes that Raytheon is offering a composite SES, and theyhave teamed with UMO Mandal to capitalize on their experience.The article notes, “the Skjold design is impressive,despite some risk. Scandinavian countries have been notoriousfor taking new hullforms and proving them out. Onlytime will tell if the SES comes back to the country thatdeveloped the technology.”Hybrid Hull Forms Offer New PossibilitiesHybrid ship hullforms are those in which total lift inthe operating or cruise mode is derived from a combinationof buoyancy, air cushion lift, or foil dynamic lift. Hybridforms offer hydrodynamic efficiency and improved seakeepingcharacteristics, while retaining the relative simplicity ofconventional monohulls and multihulls. Developments in14 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERidentified. SWG 6 concluded that the programhad the potential of significantlyincreasing the combat cost-effectivenessof NATO forces entering service after theyear 2000.Advanced Marine Vehicles are sensitiveto weight, power, and fuel efficiency.Most of these vehicles require, or theirperformance is enhanced by, an automaticcontrol system. Both Navy and commercialtechnology development haveadvanced in these areas.Structures/MaterialsThere have been even more dramaticadvancements in lightweight compositeconstruction. In its infancy in the 1970s,lightweight composite construction isFigure 3. Transport factor versus speed for a variety of AMVs and ships.now quite mature. AMV hulls were traditionallyconstructed of 5456-series aluminumto minimize weight. The yachting industryadvanced the art of lightweight aluminum fabrication. New,higher-strength, stiffer alloys were developed. Compositesoffer not only light weight, but also opportunities toincrease strength or stiffness. These characteristics can be ofgreat benefit for all AMVs, but particularly for large hydrofoilswhose hull girder is essentially supported at two points.Foils are an integral part of control systems for a wide varietyof AMV applications. Relative to the technology of theearly 1970s, newer, higher-strength, more easily fabricatedsteels offer the opportunity to construct struts and foils, notonly for hydrofoils, but for motion control systems, at muchless cost and lighter weight. Encapsulation systems can surrounda structural element with a urethane airfoil shape.This technique allows much lower fabrication cost, bettercorrosion resistance, resistance to damage, and easier repairability. Alternatively, better coatings protect struts and foilsfrom corrosion.however, hybrid hydrofoils of much greater displacementmight be feasible. Although AMVs in the 70-knot regimeare possible, speeds of 50 to 55 knots are more reasonablefor the near future.Figure 4 shows the relationship of the various majorAMVs and the relative benefits derived from each comparedto conventional displacement monohull ships.Subsequent to the ANVCE study, another comprehensivestudy performed by NATO explored a host of AMVs. 18The eight nations of the NATO Naval Armaments Group(NNAG), Special Working Group 6 (SWG 6), consisted ofCanada, France, Germany, Italy, Norway, Spain, UnitedKingdom, and the United States. SWG 6 carried out studiesto provide recommendations by which nations can decideupon their future involvement in NATO applications ofAdvanced Naval Vehicle (ANV) technology.SWG 6 work on this particular project began in 1984with the development of Outline NATO Staff Targets(ONSTs) for Hydrofoils, Surface Effect Ships (SES), andSmall-Waterplane-Area Twin-Hull (SWATH) ships. EachONST called for a multi-mission capability with emphasison the Anti-Submarine Warfare (ASW) role. The objectivewas to assess the feasibility of increasing the operationalcapabilities of NATO Naval Forces by augmenting existingand planned forces with new platforms capable of operatingat high speed and/or maintaining high mission capabilitythrough improved seakeeping under all sea conditions.SWG 6 developed seven designs to a pre-feasibility levelof detail and assessed their military value, affordability, andtechnical feasibility. The development needs for each wereHydromechanicsHydromechanics design tools advanced both for commercialand naval purposes. The AMV community now hasthe opportunity to design various hull forms, and examinea myriad of alternative shapes to determine minimumresistance. These design tools also apply to customized foilshapes for cavitation-free and minimum drag operation.Alternate control schemes, such as circulation control, canallow lighter weight, lower cost, and less complicated flightand steering control mechanics.18 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEAMulti-ModalAdvanced Naval Surface Ship AdvantagesCompared to Monohull Displacement ShipsHigher SpeedsHydrofoilsAmphibiousHovercraftACV & SESMonoHullSmallWaterplaneArea TwinHull (SWATH)Topside Deck AreaEquivalentCost/TonAutomatic ControlsMajor advances in automatic controltechnology were made. Ride control systemsfor hovercraft continued to beimproved over the last several decades.Also, although the PHM hydrofoils hadan analog control system, which occupieda compartment of its own on the ship,now a digital control system can be builtthat fits in a laptop. Furthermore, the useof hydrofoils in ride control systemsresulted in the development of muchmore efficient and effective algorithms forcontrol. This challenging component offoil design for application to all AMVswas simplified greatly. Additionally, a correspondingdecrease in control systemcost and weight occurred.ImprovedSeakindlinesFigure 4. Advanced marine vehicle relationships.During the past 10 to 15 years, catamaran hulls wereemployed by many builders, not only in the conventionalsense, but also for commercial hydrofoils. The catamaranhull offers the foil designer a higher aspect ratio with a correspondingimprovement in the lift-to-drag ratio. Therecent interest in commercial catamarans by the Navy suggeststhat catamaran, or other multihull forms, might gainacceptance for naval missions.Although the quest for friction drag reduction (FDR)goes back many decades, reducing this element of ship dragcontinues to be one of the hydrodynamicist’s major goals.Over the years, numerous techniques such as micro-bubbles,polymers, air films, highly water repellent or SuperWater Repellent (SWR) coatings, magneto-hydrodynamics,and probably others were the subjects of laboratory experiments.However, successful applications to full-scale shipswere few, if any. Nevertheless DARPA, through the use ofcomputational techniques, believes that modeling capabilitycan allow researchers to run full-scale experiments on acomputer. This capability can provide a basis for discoveringtechniques that bring optimum results. This technologycan most likely succeed and result in a major contributionto greater hydrodynamic efficiency for future higher-speedAMVs.PropulsionAdvances in naval gas turbine technologyhave fostered steady increases inpropulsion efficiency over the last 30years. Diesel technology has also improved during this timeframe. Each is lighter weight, more power-dense, and morefuel-efficient. Gas turbines have now advanced to a degreewhere they may be advantageous over diesels in high powerapplications. Gas turbines are much more common in theNavy today than they were in the 1970s. The choice of primemovers, however, depends on a specific set of missionrequirements and concepts for operations.Propulsion system technology also advanced. Very largewaterjets were developed for commercial applications. Theyare now much lighter, more efficient, and more reliable.Developments in podded propulsion systems and improvementsin propeller efficiency make propeller propulsionconsiderably more efficient. Contrarotating propulsors arenow commercially available for high-speed vehicles and canbe scaled up to the power levels required for naval AMVs.Relative to the PHM-class waterjets, propulsive efficiencygains of more than 15 percent can result using modernpropulsion technology. AMVs, and particularly hydrofoils,can also benefit from the investment made by the Navy inpodded propulsors and electric drive systems. For air cushionvehicles, air propulsion has improved with the introductionof lighter weight materials. The High Speed SealiftInnovation Center project at NSWC Carderock addressedthe technologies associated with a number of large (4,000tons and greater) sealift ship concepts. Its TechnologyCARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 19

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERDevelopment Plan (TDP) is a key reference for future workon large high-speed ships.Weapon SystemsOf all the improved subsystems that continue toprogress subsequent to the AMVs of the 1980s, advancementsin weapons, and the combat systems directing themare the most dramatic. Weapon lethality, as recently demonstratedduring Operation Iraqi Freedom, is impressive interms of accuracy, range, and power. Today, long-range pinpoint-targetingaccuracy is the norm. When applied to ships,these capabilities, combined with the high-speed maneuverabilityof some AMVs, become a valuable mission asset.High-speed ships also provide improved platforms forlaunch and recovery of Unmanned Air Vehicles (UAVs)because they can minimize the speed differential betweenthe platform and unmanned vehicles.Mission Applications of SpeedIn documenting the quest for speed at sea, we examinedthe development of various vehicle types, the technologiesthat enable them, and their limitations and relative advantages.However, it is their mission suitability, effectiveness,and costs that, in the final analysis, determine their utility asa deployed fleet asset. So, in this section, we briefly examinethe operational experience for U.S. fleet-deployed vehiclesand compare the operational characteristics and tradeoffsamong vehicle types. Finally, we briefly summarize theissues associated with the costs of development, acquisition,and operations.Since the fall of the Berlin wall, the mission and visionof the Navy evolved from a blue-water, war-at-sea focusrecounted in “Maritime Strategy” (1986), through a littoralemphasis articulated in “...From the Sea” (1992) and“Forward...from the Sea” (1994), to a broadened strategy inwhich naval forces are fully integrated into global jointoperations – “Sea Power 21” (2002). 19 A new element of thisstrategy is the development of the Littoral Combat Ship(LCS). As articulated by the CNO, Admiral Vern Clark, in“Sea Power 21,” the “stealthy and lethal Littoral Combat Shipwill add new dimensions to our ability to counter enemy submarines,small craft and mines. Designed to be smaller andfaster than any current U.S. warship, they will have themaneuverability and signature reduction to take the fight tothe enemy.” Admiral Elmo Zumwalt, a former CNO, articulatedsimilar goals when he recalled the focus of the PHMprogram he started in 1970: “Our concept was to achieve asmall, high-performance, small radar cross section, highspeed,all weather capability with sufficient armament to dealwith likely threats. Our planned use was to achieve presence inthe smaller seas, i.e. Adriatic, Aegean, Gulf of Sidra, Red Sea,Persian Gulf, Arabian Sea, Pacific Rim areas and the Balticand Black Sea.” 20 In both cases, the Navy needs an alternativefor using high-value assets for low-end missions. Forthe 29-year period ending 1999, almost 60 percent of missionsconducted by ships were low-end missions.While many of the high-speed vehicle types describedabove have been in existence for many years, we have limitedexperience in their application in actual naval missions.Of the high-speed concepts, only the hydrofoil, the air cushionvehicle, and the planing craft were operationallydeployed. However, two extensive studies were conductedproviding insight into the tradeoffs, value, and limitationsof each concept: the Advanced Naval Vehicle ConceptEvaluation (ANVCE) conducted in the United States from1975 to 1979, and the NATO assessment of Advanced NavalVehicles performed by the NATO Naval Armament Group’s21, 22Special Working Group 6 (SWG 6) from 1984 to 1987.These two studies provide a comprehensive and balancedassessment framework, and along with the limited operationalexperience, provide insight into the naval utility ofspeed. We review here the experience, trends, and tradeoffsillustrated in the two studies as they relate to the use ofspeed and vehicle tradeoffs.Operational ExperienceOf the three deployed concepts, PHM, LCAC, and PC,the LCAC and the PC are still operationally deployed.Experience shows that successful operational deploymentinvolves not only the ability to effectively perform assignednaval missions, but also integration into the Navy’s logisticsand support infrastructure.Patrol Hydrofoil Missile (PHM)The basic concept of the PHM was to operate offensivelyagainst major surface combatants and other surfacecraft to conduct surveillance, screening, and special operations.When measured against other ships, the PHM used itstop speed and employed its weapons in heavy seas thatseverely limited the effectiveness of any of the larger conventionalships. After numerous delays and changes, thesquadron of six PHMs was homeported in Key West,Florida. This decision was driven by a desire to show a “presence”in the Caribbean and support the U.S. Coast Guard inthe counter-drug mission. In the operational period from1977 to the decommissioning of the squadron in 1993, the23, 24following observations were made:20 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEA• The six PHMs, representing about 3 percent of theU.S. Navy, accounted for 26-29 percent of all surfaceNavy drug seizures over the ten-year period endingin 1993. The street value of the drugs seized byPHMs amounted to $1.1B, or 5 times the cost tooperate the PHM Squadron over that period of time.• From March 1983 to February 1987, the PHMSquadron amassed over 4,400 days underway with avoyage reliability rate of 97 percent.• Three of the PHMs achieved 100-percent availabilityin a 90-day forward deployment to Grenada, endingin May 1987.• The PHM Squadron staff, six ships, and their MobileLogistic Support Group evolved to a personnelrequirement in 1992 of 43 officers and 362 enlisted.This number is roughly equivalent to the crewaboard a destroyer-size ship.• The PHMs actually cost about $3M per ship per yearto operate, about 1/3 the cost of a FFG-7, or 1/5 thecost of a Spruance-class destroyer.Landing Craft Air Cushion (LCAC)The LCAC is an air cushion craft designed for transporting,ship-to-shore, personnel, weapons, equipment, andcargo of the assault elements of the Marine Air-GroundTask Force. They are capable of carrying heavy payloads(60-75 tons), such as an M-1 tank, at speeds in excess of 40knots to the shore and across the beach. This unique combinationof high speed and all-terrain capability is a dramaticinnovation in modern amphibious warfare technology.The LCAC enables launching assaults from points overthe horizon, thereby decreasing risk to ships and personnel,and it creates a greater uncertainty in the enemy’s mind.Starting in 1987, the Navy acquired 92 LCACs to date andhas conducted operations around the world, including theArctic. The largest deployment of LCACs took place inJanuary 1991 with four detachments consisting of elevencraft in support of Operation Desert Storm. The LCAC,which is deployable on six different classes of Navyamphibious ships, can reach more than 70 percent of theworld’s coastlines, compared to only 17 percent with conventionallanding craft.Cyclone-Class Coastal Patrol Ship (PC-1)The primary mission of these ships is coastal patrol andinterdiction surveillance, an important aspect of the Navy’slittoral strategy. These 35-knot craft are able to transportsmall SEAL teams and their specialized delivery craft, orCoast Guard boarding teams, for counter-drug inspectionsand homeland-security operations. The USS Cyclone (PC-1)was commissioned in August 1993 and transferred to theU.S. Coast Guard in August 2000. Of the thirteen remainingcraft, nine operate out of Little Creek, Virginia, and four outof the Naval Amphibious Base, Coronado at San Diego, CA.They have limited endurance for their size. These Navy vessels,slated for decommissioning in 2002, after September11, will remain active in support of homeland security tasks.One of the craft, PC-14, was modified with a stern ramppermitting launch and recovery of a Naval Special WarfareRIB (Reinforced Inflatable Boat) while underway, an importantLCS capability. The PC-14 also incorporates reducedradar, electro-optic, and infrared signatures.Operational Characteristics and TradeoffsThe two studies mentioned above, ANVCE and theNATO SWG 6 assessments, represent an important frameworkfor comparing operational and ship characteristicstradeoffs. The ANVCE study considered nine generic conceptsthat generated 23-point designs using common criteriaand payloads. The NATO study considered three genericconcepts and generated seven-point designs also usingcommon criteria and payloads. The resulting performanceattributes of each concept were then compared and assessedby a team of experts. The following concept characteristics,taken from both studies, are provided to illustrate the operationallimitations and advantages of the use of speed at seaas they might relate to the LCS:• Overall speed comparison• Days per year of sustained operations at speed• High and low speeds operability in a seaway• Range capability versus speed• Mission payload weight trends• Overall Speed ComparisonWhile maximum speed in calm water is an importantdesign parameter, for military operations the speed in roughwater may be a more significant measure. Figure 5, fromReference 22, shows a comparison of the predicted maximum,continuous, calm water-speeds of the point designsconsidered in the NATO study. Also assessed is the annualaverage maximum speed sustained in the North Atlantic.The concepts are ordered by the sustained speed in roughwater and include a U.S. hydrofoil, Spanish SES, French SES,U.S./German SES, Canadian hydrofoil (surface-piercingconfiguration), U.K. SES, and a SWATH ship. A NATOfrigate design (NFR 90), and the FFG-7 are included forcomparison.CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 21

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYER• Days Per Year of Sustained Operations atSpeedSpeed, combined with limitations ofweapons systems and crew effectiveness, measuresthe operational availability of a vehicle as aneffective weapons system. The NATO studiesassessed the operational availability (days peryear) as a function of speed of each concept inthe same North Atlantic environment, as illustratedin Figure 6. These calculations include theoperational limitations of each concept typesuch as foil borne broaching, pitch angles > 3degrees, and significant vertical accelerations atthe bridge. For most of the year, the SESs andthe hydrofoils have a clear sustained advantageover the monohulls (FFG-7 and NFR 90).• High and Low Speed Operability in aSeawayThe LCS is anticipated to operate in asprint-and-drift mode for many of itsoperations, so low-speed operability isalso important. The PHM-1, in a 12-dayexercise off Hawaii called RIMPAC-78, 25accumulated over 167 underway hourswith 65 percent at low speed and an averagespeed-of-advance of 21.14 knots. TheNATO study examined the operability athigh and low speeds of the point designsin the northern North Atlantic in winter.Figure 7 illustrates the results of thatassessment.DAYS PER YEAR IN WHICHGIVEN SPEED CAN BE SUSTAINEDSPEED (KNOTS)605040302010050.040.6USHYDRO-FOILMAXIMUM CONTINUOUS CALM-WATER SPEEDANNUAL AVERAGE MAXIMUM SUSTAINED SPEED IN NORTH ATLANTIC52.038.7SPSES57.038.6FRSES55.038.2US/GSES45.038.1CAHYDRO-FOILFigure 5. Comparison of speed capability.300200100CONDITIONS:NORTH ATLANTICANNUAL AVERAGEFULL LOADDISPLACEMENTFFG 7SWATHNFR 9050.034.7UKSESUK SES30.023.528+22.525.822.1NFR 90 FFG 7 SWATHCA HYDROFOILUS HYDROFOILUS/G SESFR SES• Range Capability Versus SpeedEfficient multi-mode operation athigh and low speeds is an importantdesign consideration for the LCS. Figure 8shows the predicted distance covered perton of fuel for each LCS point design as a function of speed.The data show that the range of the SES and the hydrofoilcan be extended considerably by resorting to hullborneoperation. In comparison, the range of the SWATH ship andthe FFG-7 can increase range only slightly by reducingspeed.010203040MAXIMUM SUSTAINED SHIP SPEED KNOTSFigure 6. Days per year versus maximum sustained speed for NATO ANVs.the Hydrofoil Point Designs have smaller payloads because oftheir smaller size. Their payload weight fraction, however, isconsistent with those of comparable monohulls. The SWATHship, however, has a payload which is some 42% below thetrend line established on the basis of full-load displacement.”50• Mission Payload Weight TrendsFigure 9 shows the mission payload weight as a functionof full-load displacement for the point designs in boththe ANVCE and NATO studies. The NATO study observed:“All the Point Designs carry considerably less mission-relatedpayload than their respective baseline monohulls. The SES andCost of SpeedIn the final analysis, cost may be the most importantdeterminant in deploying high-speed ships at sea. Is the costworth the additional flexibility and mission effectivenessoffered by the higher speeds? A cost assessment is the focus22 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

CB = CUSIONBORNEFB = FOILBORNEHB = HULLBORNE100PERCENT OPERABILITY806040200HBUKSESCB/RC27-40.5 KT11-17 KTRC = RIDE CONTROLFS = ACTIVE FIN STABILIZERSFRSESCB35-52 KT12-18 KTUS/GSESCB/RC30 KT20 KTU.S. CAHYDROFOIL HYDROFOILHB FB/RC FB/RC44-48 KT 45 KT8-16 KT 15 KTSHIP OPERABILITYHELICOPTER OPERABILITYCASWATHHB25 KT10 KTFPG 7HB/FS25 KT10 KTDD 963HB/FSFigure 7. Comparison of percentage operability at high and low speed in Area 1of N. Atlantic in winter.N. MILESM. TON4030201000SWATH10MILES / TON FUELHB20CB/FB30SPEED, KNOTSUS HYOUS/G SESW.J.S.P. PROPUS HYOFR SESUK SESFR SES FFG 7Figure 8. Comparison of range per unit of fuel.40US/G SESUK SESFR SESUS HYOS.P. PROPW.J.50THE QUEST FOR SPEED AT SEAof the two comprehensive studies mentionedabove. Both establish a set of commonstandards and payloads that permitsa more consistent cost-estimatingmethodology.Vehicle Technology Development CostsAn aspect of cost not always discussedis the cost of developing the vehicletechnology itself. This cost includesthe basic and exploratory research (6.1and 6.2) in the Navy’s RDT&E accountingmethod, the advanced development (6.3)which examines and demonstrates totalsystem technologies, the engineeringdevelopment (6.4) devoted to pre-acquisitionresearch on a specific configuration,and the actual ship constructioncosts, Ship Construction, Navy (SCN).The hydrofoil concept has the most completehistory of these costs, starting in1949 and ending in 1980 with the finalSCN and RDT&E appropriations. This program resulted intwo research vehicles (PCH-1 and AGEH-1) and eight operationalvehicles (PGH-1 and 2, and six PHMs). The proportionsof the total cost over the thirty-year research programand fleet deployment are• Basic Research & Exploratory Develop.(6.1+6.2) 3.0%• Advanced Development (6.3) 17.8%• Engineering Development (6.4) 15.5%• Ship Construction, Navy (SCN) 63.7%Laying the technical foundation of a vehicle technology(6.1 to 6.3) represented about one-fifth of the total conceptdevelopment cost resulting in a fleet deployable concept.Acquisition CostsAcquisition costs are related to speed as well as vehiclesize. As mentioned before, the ANVCE Study examined 23different point designs and applied a common cost-estimatingmethodology to all designs. Figure 10, taken fromReference 26, is compiled for two classes of ships, a 3,000-ton and a 1,000-ton displacement class. The absolute valuesare ratios of the FFG-7 costs. Peter Mantle, the TechnicalDirector of the ANVCE study, states: “The cost of going fasterincreases almost linearly until the dynamic (lift) vehicles comeinto play (i.e., hydrofoils, air cushion vehicles, and surfaceeffect ships), at which time speed comes relatively easily andcheap. However, it will be noticed that the cost of such vehiclesover a conventional warship (FFG-7) is greater than 2:1”. 27CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 23

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYERMISSION PAYLOAD, MT1000900800700600500400300200100US/G SES LUPGFR SES UK SESUS HYDROFOILCA HYDROFOIL00 2000 4000 6000 8000 10000FULL-LOAD DISPLACEMENT, MTOperating and Support CostsOperating and support costs range from 52 percent to69 percent of the total life-cycle cost, which includes development,acquisition, and operating and support costs. TheNATO SWG 6 study examined operating and support(O&S) costs for the six advanced ship point designs.Lifetime O&S costs consisted of the following cost elements:direct personnel, operations (less fuel), fuel, direct maintenanceand modernization, recurring investment, and indirectcosts. Table 1 compares the proportions of the annualizedO&S cost per ship for an average of the four SESdesigns, and an average of the two hydrofoil designs comparedto the FFG-7.Although size and payload differ significantly, the higher-speedvehicle requires a smaller crew than the FFGs, mostprobably due to an increase in ship automation. However,the percentage of the annual O&S cost in terms of fuel significantlyincreases.SummaryPAYLOAD FRACTION 10%FFG 7NFR 90TRIBALFigure 9. Comparison of mission payload.A serious question remains: afterall this scientific and technical development– why does the Navy nothave higher-speed ships? The answeris as complicated as the technologiesrequired to increase speed at sea.The quest for higher-speed shipscompetes for a share of limited fiscalresources. In addition, because Navyculture and career incentives preferDD 963PAYLOAD FRACTION 6%CA SWATHMISSION PAYLOADCOMMAND & SURVEILLANCE ISWGS 4001ARMAMENT ISWAS 7001MISSION EXPENDABLES ISWAS F20 & F421larger ships with larger crews, it is perceived thatwe must modify the Navy’s support and logisticinfrastructure to accommodate such new technologies.These changes constitute major disincentives.Despite these disincentives, several highspeedvehicles have already found their way intonaval service. The most notable example for theU.S. Navy is the Landing Craft Air Cushion(LCAC). The LCAC is an ideal means of transportingtroops and heavy equipment from a standoffposition many miles from shore, through the littoral,across beaches and marshes to solid ground,and farther inland. It would seem, however, thathigh-speed ships are not yet fully integrated intothe Navy’s current strategic and tactical thinking.As the nature of the threats to the UnitedStates and other major maritime powers changesin the 21st century, the long-recognized technicaladvantages of high-speed and shallow-draft, aircushionvehicles are likely to receive even greater attention.With the emphasis in the U.S. Navy’s new vision on littoralwarfare expressed in “Sea Power 21,” and the new role of theDepartment of Defense in dealing with asymmetric threatsposed by terrorists, rogue states, and criminals who use thehigh seas, it may well be that the time for higher speed shipshas arrived. If so, the Carderock Division will, as it has inthe past, be an integral part of the persistence in developingthe technology necessary to continue the quest for speed atsea.References*1. Savitsky, Dr. Daniel, Chapter IV “Planing Craft,”Modern Ships and Craft, Naval Engineers Journal, February1985.2. Jansson, B.O. and Lamb, G.R., “Buoyantly SupportedMultihull Vessels,” Proceedings of the Intersociety HighPerformance Marine Vehicle Conference, Arlington, VA, 24-27 June 1992.Table 1. Annualized O&S Cost% of Annualized O&S CostO&S Cost Categories Avg. SES Avg. HYD FFG-7• Direct Personnel 19% 17% 32%• Operations (less fuel) 13% 14% 14%• Fuel 37% 21% 17%• Direct Maintenance and Modernization 25% 39% 31%• Recurring Investment 4% 7% 4%• Indirect Costs 2% 2% 2%24 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

COST RATIO3.02.01.00010FFG 7Figure 10. The cost of speed.SWA 4HIGHLB SESMONO 3HYD 21000 TONNE CLASSKEYCUSHION VEHICLESHYDROFOILSDISPLACEMENT VEHICLES20 30 40 50 60 70 80 90 100SPEED IN SEA STATE 3 (KNOTS)3. SNAME T&R Bulletin No. 1-45, “AlternativeHullforms for U.S. High Performance Ferries,” 1996.4. Wilson, M.B. and Hsu, C.C., “Wave CancellationMultihull Ship Concept,” Proceedings of the IntersocietyHigh Performance Marine Vehicle Conference, Arlington,VA, 24-27 June 1992.5. Eames, Michael Curtis, “A Review of HydrofoilDevelopment in Canada,” First International HydrofoilSociety Conference, Ingonish Beach, Nova Scotia, Canada,27-30 July 1982.6. Johnston, Robert J., “History of the U.S. Involvementin Developing the Hydrofoil,” First International HydrofoilSociety Conference, Ingonish Beach, Nova Scotia, Canada,27-30 July 1982.7. Browne, R. “Running with Sea Legs,” Gibbs & Cox,Inc., Author trip report (Sept. 1958), 10-U02829M DTRCAdvanced Ship Data Bank.8. Ellsworth, William M., “Twenty Foilborne Years—The U.S. Navy Hydrofoil High Point PCH-1.” David TaylorNaval Ship R & D Center Report, September 1986.9. Stevens, Don L., Jr., “The Bureau of Ships HydrofoilCraft FRESH-1,” Meeting of the Chesapeake Section,SNAME, Washington, DC, 26 February 1964, 10-U00034MDTRC Advanced Ship Data Bank.10. Johnston, Robert J., “Modern Ships and Craft,Chapter V, Hydrofoils,” Naval Engineers Journal, February1985.11. Olling, David S., and Merritt, Richard G., “Design,Development, and Production of the Patrol CombatantPC3000 TONNE CLASSHYD 7SES 3ACV 3ACVTHE QUEST FOR SPEED AT SEAMissile (Hydrofoil)—A Brief History,” BoeingMarine Systems Report.12. Stanton-Jones, R., “The Developmentof the Saunders-Roe Hovercraft SR.N1,”Symposium on Ground Effect Phenomena atPrinceton, Paper 13, 21-23 October 1959.13. Lavis, David R., and Spaulding, KennethB. Jr., “Surface Effect Ship (SES) DevelopmentWorldwide,” Chesapeake Section, Society ofNaval Architects and Marine Engineers, 12March 1991, Meeting, Arlington, VA.14. Gabrielli, G. and Von Karman,Theodore, “What Price Speed?” MechanicalEngineering, Volume 72, October 1950.15. Kennell, Colen, “Design Trends inHigh-Speed Transport,” Marine Technology,Volume 35, No. 3, July 1998, pp. 127-134.16. Kennell, Colen, et al, “High-SpeedSealift Technology,” Marine Technology, Volume35, No. 3, July 1998, pp. 135-150.17. Advanced Naval Vehicles ConceptEvaluation (ANVCE) Project, Volume II,Technical Evaluation, December 1979.18. Assessment of Point Designs, Volume II, DetailedAssessment, NATO Naval Armament Group, SpecialWorking Group 6 (SWG 6) On Naval Vehicles, November1987.19. Office of the CNO, “Seapower-21 Series,” U.S.Naval Institute Proceedings, October 2002 to January 2003.20. Zumwalt, E. R., Admiral, “Comment Made to theInternational Hydrofoil Society,” June 1995.21. (OP-96), “Advanced Naval Vehicles ConceptEvaluation (ANVCE),” Project Summary, Volume 1,December 1979.22. NATO Naval Armaments Group Special WorkingGroup 6 on Naval Vehicles, “Assessment of Point Designs,Volume II, Detail Assessment,” Report No. AC/41 (SWG 6)D21, November 1987.23. Jackson, Les J., “Recent PHM OperationalExperience,” High Performance Marine Vehicles Conferenceand Exhibit, Washington, D.C., 24-27 June 1992.24. “PHM History 1973 Through 1993,” InternationalHydrofoil Society.25. “PHM Development Experience-RIMPAC-78,”10-U1551L, DTMB Advanced Ship Data Bank, September1985.26. (OP-96), “Advanced Naval Vehicles ConceptEvaluation (ANVCE),” Project Summary, Volume 3,December 1979.27. Mantle, Peter J., “Introducing New Vehicles,”Modern Ships and Craft, Naval Engineers Journal, February1985.CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 25

DENNIS J. CLARK, WILLIAM M. ELLSWORTH, AND JOHN R. MEYER*Note: Most references are available from the websiteof the International Hydrofoil Society. They are also availableon AMV compact discs that are available from the IHSfor a small fee.Dennis J. Clark worked at theCarderock Division of theNaval Surface Warfare Centerfor nearly 40 years in a widevariety of positions prior tohis retirement in January 2003. He has beenDirector of Strategic Planning, Assistant TechnicalDirector, Head of the Costing and Design SystemsOffice, Deputy Head of the Advanced ConceptsOffice, Manager of Systems Integration in theAdvanced Hydrofoil Development Office, and leadstructural researcher for the Hydrofoil Office. He isa charter member of International Hydrofoil Societyand throughout his career he has supported thedevelopment of advanced vehicles through a numberof activities: developed the Advanced Ship DataBank (currently containing over 15,000 documentson advanced vehicles); led the development of a totalship early stage design tool called ASSET (AdvancedSurface Ship Evaluation Tool) for a variety of shiptypes (surface combatants, hydrofoils, SWATH ships,and tri-hull concepts); led the development of costestimating capability for advanced technology andvehicles; and promoted innovation through a numberof venues by serving as chairman of Carderock’sInvention Evaluation Board for the last ten years,promoting the development of Carderock’sInnovation Center, and functioning as ONR’s leadresearcher on the Concept Assessment of Platformsand Systems task. Mr. Clark is an engineering graduateof City College of New York and has completedgraduate work toward an MBA at GeorgeWashington University.William M. Ellsworth P.E.graduated from the Universityof Iowa in 1948 with an M.S.in Mechanical Engineering,majoring in Fluid Mechanics.Upon graduation, he joined the David Taylor ModelBasin Hydromechanics Laboratory as a ProjectEngineer. Over the next ten years, he completedcourse work for a Ph.D. in Aeronautical Engineeringand held various positions in the HydromechanicsLaboratory, ending as the Head of the TowingProblems Branch.He left DTMB in 1958 and joined the newlyformed Systems Engineering Division of PneumoDynamics Corp. as Head of Marine Engineering. Heheld various positions over the next six years endingup as Division General Manager and Corporate VicePresident.In 1964, at the invitation of Dr. William E.Cummins, Head of the Hydromechanics Laboratory,he returned to the David Taylor R&D Center asHead of the Hydrofoil Technical DevelopmentProgram. In 1969, he was appointed AssociateTechnical Director for Systems Development, andHead of the newly created Systems DevelopmentDepartment, initially as GM-17, and later as an ES-4 in the Senior Executive Service. He was responsiblefor the development of advanced naval vehiclesincluding hydrofoil craft, air cushion craft, amphibiousassault craft, Small-Waterplane Twin-Hull(SWATH) ships, advanced submarine concepts,mobile ocean bases, and shipboard material handlingand transfer systems.He retired from federal service in January 1983and joined Engineering & Science Associates (ESA),a small group of consultants, as Vice President. Overthe next ten years, he provided consulting services inmarine systems and advanced naval vehicles to avariety of government, academic, and commercialactivities. He wrote a book on the Navy’s experimentalhydrofoil Highpoint (PCH-1) entitled “TwentyFoilborne Years.” He also assisted Dr. RodneyCarlisle in the writing of the 100-year history of theDavid Taylor Research Center, entitled “Where theFleet Begins,” and served as the co-chairman of theEditorial Advisory Board.26 CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST

THE QUEST FOR SPEED AT SEAWhen ESA disbanded in 1994, he formedEllsworth Engineering as a sole-proprietorship andcontinued to provide consulting services to governmentand industry up to the present time.He received the David Taylor Medal in 1967,the Navy Civilian Service Award in 1972, the ASNEGold Medal in 1974 as Naval Engineer of the year,the Navy Distinguished Civilian Service Award in1980, and the Senior Executive Service MeritoriousPresidential Rank Award in 1980.He is currently a Fellow and Life Member ofASME, a life member of ASNE, a member of the U.S.Naval Institute, and a licensed Professional Engineerin the State of Maryland.John R. Meyer holds B.Ae.E.and M.Ae.E. degrees inAeronautical Engineeringfrom Rensselaer PolytechnicInstitute, and has done additionalgraduate work in the same field at theMassachusetts Institute of Technology. He joined theNaval Surface Warfare Center, Carderock Division(NSWCCD) in 1971, was associated with AdvancedNaval Vehicles in the Advanced Concepts Office, andthen served as Manager of Hydrofoil Technology inthe Hydrofoil Group of the Ship Systems Integrationand Programs Departments. He has authored manyNSWCCD reports, American Institute of Aeronauticsand Astronautics, and American Society of NavalEngineers papers on the subject of hydrofoils andhybrid marine vehicles. He retired from the Centerin 1997 and has been active as a consultant in thisfield. Among other projects, he has been working ona project for the NSWCCD involving the PlaningHYSWAS Integrated Mode (PHIN) UnmannedSurface Vehicle.He currently serves as President of theInternational Hydrofoil Society. Prior to employmentat NSWCCD, he held several research anddevelopment, long range planning, and engineeringmanagement positions with Boeing-Vertol, Trans-Sonics Inc., Air Force Cambridge Research Center,and the Aero-Elastic Laboratory at M.I.T.CARDEROCK DIVISION, NSWC — TECHNICAL DIGEST 27